WB135/35 and WB140/35/FB

These two airfoils were designed by “Woody” Blanchard Jr. The first is the original and the second is a modified, flat-bottom version with the same camber line as the original. Consequently the second has more aft thickness which leads to substantially different performance.

It is interesting to note that although the WB135/35 and MB253515 have similar upper-surface contours, the behavior of the airfoils is quite different (see Fig. 11.11). The MB253515 shows the strong effects of a laminar separation bubble at Rn of 100k, whereas the WB135/35 shows just the opposite trend— relatively low drag at 100k. The modified version, however, does have a drag- producing laminar separation bubble at 100k. Other than for ease of building, the flat bottom does not appear to be advantageous.